The biochemistry core of this program project grant supports all the individual sections by providing sophisticated quantitative and qualitative assays for a number of lipids using mass spectrometric techniques. Most of the quantitation of lipids is carried out by stable isotope dilution mass spectrometry using isotope labeled internal standards to correct for losses during isolation and purification. Quantitative assays employ LC/MS, tandem mass spectrometry (LC/MS/MS), positive ion electron ionization GC/MS, and negative ion chemical ionization GC/MS as the major analytical techniques. Specific assays have been developed over the years and are a part of the routine assays available in the biochemistry core including quantitation of primary prostaglandins, leukotrienes, combinations of these arachidonate metabolites (eicosanoid profile), platelet activating factor (PAF), lyso-PAF, cholesterol, and the major phospholipid classes including glycerophosphocholine and glycerophosphoserine molecular species. In addition, fatty acids are quantitated as a fatty acid profile where the major fatty acid between Cn-C22 are analyzed in a single GC/MS run. Nonenzymatic oxidized metabolites of arachidonic acid (isoprostanes) are also quantitated by either GC/MS or LC/MS/MS techniques. Qualitative analyses are also carried out in the core facility as well as methods development when the specific need arises. In general, these techniques will employ mass spectrometry as the quantitative tool for precise and accurate assays. Methods development may also lead to the implementation of methods in the investigators own laboratory. The staff of the biochemistry core are skilled in the operation of mass spectrometers and the application of mass spectrometry in the development of precise methods used in lipid biochemistry.